A fishing reel has many rotary members such as a rotor, a spool, and a handle shaft, and such rotary members are rotatably supported with a reel main body or other parts through bearings. In fishing reels, a ball bearing is typically used as a bearing. This type of bearing comprises an outer ring 3 and an inner ring 4 disposed at an interval from each other, rolling elements 7 provided in contact with these, and a retainer 8 retaining the rolling elements 7 at predetermined intervals, as shown in FIG. 6, and a space between the outer ring 3 and the inner ring 4 usually communicates with the outside.
Generally, a fishing reel is used in an environment exposed to water, and water therefore enters inside the reel and is prone to cause the corrosion of the bearings. In addition, when a fishing reel is used in an environment exposed to seawater, the seawater enters the gaps between rolling elements and the raceway surfaces on the outer ring and inner ring of a bearing, the seawater crystallizes out and may hinder the rotation of rotary members and cause an abnormal noise and fixation, which is so-called salt engagement. Therefore, in fishing reels, it is necessary to prevent the corrosion of members such as bearings and prevent a decrease in rotation function due to the crystallization of seawater.
Bearings used in fishing reels are usually made of stainless steel excellent in corrosion resistance as well as hardness and impact resistance. When a fishing reel is used in an environment exposed to seawater, and the like, however, high corrosion resistance is required, but the properties of stainless steel itself may be solely insufficient for the corrosion resistance.
In order to address defective rotations due to salt engagement, conventionally, as shown in FIG. 6, has been used a bearing 20 comprising a shield 9 made of an elastic body which is provided between an outer ring 4 and an inner ring 5 in a state of being in contact with these. This shield 9 is effective in preventing the entry of seawater into the space between an outer ring 3 and an inner ring 4, but the shield 9 is provided in contact with both of the rings in order to prevent the entry of seawater, and therefore has a problem that increase in a load is caused when the outer ring 3 and the inner ring 4 rotate relatively.
In this regard, Patent Literatures 1 and 2 propose a bearing in which a magnetic fluid is retained at a predetermined place in the space between an outer ring and an inner ring by magnetic force to prevent the entry of seawater. An advantage of this bearing is that a fluid is in contact with an outer ring and an inner ring, and therefore a load thereon is small when they rotate relatively. This bearing however requires a member such as a magnet for retaining the magnetic fluid at a particular position and has a problem of becoming large and also expensive. This bearing also has another problem that magnetic precipitates are developed and adhere to an outer ring and an inner ring.
On the other hand, Patent Literature 3 proposes a reel in which particles of a fluorine compound or silicon compound are applied at the vicinity of the opening of a housing of the reel to prevent the entry of water thereto. This reel can prevent the entry of water thereto at a certain level, but the effect cannot be said to be sufficient.
Patent Literature 4 proposes a bearing in which the exposed surfaces of an outer ring and an inner ring are treated with chromic acid to increase corrosion resistance, and the space between the outer ring and the inner ring is filled with water-repelling grease or oil. In this bearing, it is possible to prevent seawater from entering the space between the outer ring and the inner ring, without requiring an additional member such as a magnet, and further improve corrosion resistance of the outer ring and the inner ring. In this bearing, however, seawater is prone to crystallize on the exposed surfaces of the outer ring and the inner ring, and the salt formed here enters the space between the outer ring and the inner ring and may cause salt engagement. In addition, since the space between the outer ring and the inner ring is filled with a water-repelling material, this bearing has a problem that the load somewhat increases during rotation: particularly when the space between the outer ring and the inner ring is filled with a water-repelling material having relatively high viscosity, such as water-repelling grease, the load during rotation increases.